Automatic auxiliary fuel pump system



Mmh 11, 1947-.r

H. A. sAT'rL-:RLEE 27,417,215 AUTOMATIC AUXILIARY FUEL PUMP SYSTEM Filed Aug. 25, 1941 2 sheets-sheet 1 Mar'ch 11, 1947.

H. A. SATTERLEE 2,417,215 AUTOMATIC AUXILIARY FUEL IvUMP SYSTEM File@ Aug. 25. 1941 2 sheets-sheet 2 *40 5f Q Z/ u 75 Engneil 4J Pressure.

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@gan/y raient-limi. ii. ist? i i STES I Y 2,411,2i trice f PATENT 2,411,215 y Acronimo Ar rum.

. SYSTEM 'Howard vSutter-lee, The Aro Equipment .Bryam'ohia assigner to Corporation, Bryan,l Ohio, x

a corporation of Ohio i Application August 25, 1941, Serial No. 408,233

i2 Claims.

My present invention relates in general to an automatic fuel pump system provided with a plurality of separate fuel sources wherein the contents from a plurality of fuel containers are automatically connected in predeterminedorder to a source of fuel consumption, such as an aeroplane engine or the like, the general features of such a system being shown in the David Samiran application Serial No. 261,542, filed March 13,v

buretor or fuel injector of the engine when starting the engine in order to afford proper operation ofia fuel pressure switch and the function of supplying fuel to the engine when fuel through the engine driven pump of the system fails as a result of failure of fuel in a tank connected by an automatic selector valve with the engine driven fuel pump.

Another object is to provide in connection with an automatic selector valve controlled by a fuel pressure responsive switch, an electric operating circuit which causes operation of the electric fuel pump at the proper times, depending'upon various cycles of operation of the fuel system occurring.

Still another object is to provide a reserve fuel tank from which the electric pump receives fuel and an automatic means to keep the reserve tank lled with sumcient fuel for a number of electric pump operations, regardless of the number, of electric pump operations necessary during the functioning of the fuel system. l

A further object is to provide the electric pump so connected with the fuel pressure switch that it is controlled thereby in conjunction with a manual switch operable upon starting of the engine to effect a slow rotation of the electric pump to prevent improper carburetor or fuel injector action, and, at the same time, ll the conduit system with fuel so that the engine is ready to start'by the time its starting mechanism functions.

A further object is to provide yan automatic fuel system wherein an electric pump automatically suppliesfuel until such time as an engine driven pump supplies fuel at a predetermined and slightly greater pressure sumcient to operate the engine, whereupon the electric pump is cut oif and remains idle until the engine is again started, or until such time as fuel from one source fails and a selector valve then operates to connect the carburetor or fuel injector with another source,

`the electric pump during the change-over period' l 2 supplying fuel for the requirem buretor or fuel injector.

With these and other objects in view, my invention with respect to its features which I believe 5 to be novel and patentable will be pointed out in the claims appended hereto. For a better de tailed understanding of the invention, and furents of the car ther objects relating to details of economy of myinvention, reference is made to the following lo description and to the accompanying drawings wherein such further objects will definitely appear, and'in which: c c Figure 1 is a diagratic View of a portion of a fuel system with an auxiliary fuel pump ein bodying my invention connected therein. Figure le is a similar diagrammatic view of the remaining 4portion of the fuel system, Figure le being a continuation of Figure l. 4

Flgure`2 is a diagrammatic view of the fuel pressure switch of the system showing the parts in a different position as when the fuel system is functioning to supplyI fuel by the engine driven pump to the carburetor or fuel injector.

Figure 3 is a similar diagrammatic View showing theposition of the fuel pressure switch when fuel pressure rises following a selector valve operation; and

Figure 4 is a sectional view on the line 4--4 of Figure 1 showing a by-pass Valve arrangement.v

On the accompanying drawings I have usedthe reference character C to indicate generally a carburetor or fuel injector. An air eliminator is in dicated at. AE, afuel pressureV switch at PS, an

engine driven fuel pump 'at P1, an electric fuel pump at P2 and a strainer at S. A plurality of fuel sources, such as a main tank TA1, an auxiliary tank T2, and a reserve tank T3, are connected by a selector valve SV with the strainer S.

The carburetor C has a fuel supply pipe 3u 4o which feeds fuel through suitable passageways to,a spray nozzle il.: The spray nozzle 3i opens only when the fuel is above a predetermined pressure, such as six pounds. The nozzle, by way of example, may have a diaphragmi responsive 4,5 .to the fuel pressure and opened against the bias of a spring 33. The nozzle then discharges atomized fuel into4 the air intake 34 of the carburetor C. Obviously, instead of the carburetor, the fuel may be supplied to a fuel injector such as now 5o used in connection with aeroplane engines.

A conduit 30 is adapted to receive fuel either through 'a conduit 35 from the electric pump P2 or through'conduits 36 and 3l from the'` engine driven pump P1. Between the conduits 36 and 3l the air ellminator.AE is mounted, and between the air eliminator and the conduit 36 I provide a check valve 33. Ther air eliminator is fully described in the aboverreferred to Samiran application, and includes, briefly, a housing 3Q adapted to receive the fuel from the pump P1 and to eliminate air and vapor therefrom through a conduit 40 discharging back into one of the fuel tanks, such as T3. The air and vapor flow is controlled. by a float valve 4|, the oat thereof being indicated at 42. The valve 4| is adapted -to seat in an opening 4i!11 when the iioat is raised. The air and vapor are further controlled by a disk-like vent valve 43 having a. spring 44 backing it and set, for instance, lat ten pounds pressure. The pressure at which the vent valve 43 opens is modied by pressure on the top of the valve disk, which pressure may be either atmospheric pressure through a conduit 45 or supercharger pressure where the engine is of supercharged type. In that case the outlet pressure of the supercharger is introduced through the conduit 45 to the top of the vent valve 43.

The carburetor C may also have an air eliminator float valve 4I, the oat being indicated at l211 and the air and vapor eliminating conduit at 4ll connected with the conduit 40.

'I'he selector valve SV includes a rotor 4S adapted toconnect an outlet conduit 41 with any one of three or more inlet conduits such as t8, e9 and 55. The conduit 43 extends from the main fuel tank T1 and the conduit 419 extendsfrom the auxiliary vfuel tank T2. The conduit connects with a stand pipe I in the reserve fuel tank T3 so that it can receive only a portion of the fuel therefrom, the remaining portion being left as a reserve for the electric pump P2.

4 SS1 is provided which is operated by a cam 1li on the selector valve shaft 5B. Another switch SS. which may be termed a "slow switch. is operated by a second cam 'Ilj also oni the selector valve shaft 5B. The slow switch SS2 is adapted to control the speed of the selector valve motor SM by permitting it to rotate at low speed when the slow switch SSn is open. In that case the current ows througha resistance R? to cut down the energization of the motor.

The engine driven pump P1 has a bi1-pass return valve 'I2 which may be set for fourteen pounds. The electric pump P"1 has a similarv lby-pass return valve 'I3 which may be set for The selector valve SV is operated by a selector valve motor SM in a manner fully disclosed in Samiran Patent No. 2,275,471. Briefly, the operative connection between the motor SM and the selector valve rotor d6 includes a bevel pinion 52, a bevel gear 53, step-down gears 54 and 55, and a selector valve shaftv 5B.v The bevel gear 53 may be clutched and declutched relative to the pinion 56 by a solenoid S2 operative, when energized, to engage a toothed clutch. element 51 with a similar toothed clutch element 58. The element 5l is slldably and `non-rotatably mounted onashaft 5S to which the gear 54 is secured,4

andthe clutch element 58 is secured to the bevel gear 53. When the solenoid S2 is energized it engages the clutch elements with each other.

The selector valve shaft 56 is shown extended to a dial 6U with which a hand lever 6I cooperapproximately leleven pounds. The pump Pz has a second by-pass return valve 14 (see Figure 4) set at three pounds, or thereabouts. Passageways leading past the valve 'lare restricted for a purpose which willshereinafter appear.

For operating the pump P2 an electric pump motor PM is provided. The pump P2 receives fuel ,through a conduit 15 from the reserve fuel tank T1. i

A circuit arrangement is provided for the various elements ofthe fuel system described and includes a source of electric current, such as a battery I2, grounded through a wire I0. A wire I'extends to an ignition switch IS from which a wire I4 leads to the contact El of the pressure switch PS. The ignition switch IS is for the ignition system of the engine on which the fuel system is installed, a wire lla being the wire leading to the ignition mechanism.

The pressure switch contact 68 is connected by a wire I5 with one side of a selector switch SS3. nected by'wire I5, 20 and 20a to the slow switch SS2, from the other side of which a wire I1 extends to one side of.the selector valve motor SM. -The other side of the selector valve motor is grounded. The wire 20 also connects the wire I6 with one side of the stop switch SS1. The other side of the stop switch is connected by a wire 2l with the solenoid S1, which also has one side tion, and to be automatically moved to on posiates to manually operate the selector valve when necessary or desirable, and to indicate the position of the selector valve at all times.

' The pressure switch PS is also disclosed in the last mentioned Samiran application, as well as in Samiran Patent No. 2,291,654, issued August 4, 1942. Briefly, it includes a diaphragm 62 subjected to the fuel pressure by means of a conduit 63 connected with the conduit 31. phragm 62 is in the retracted position of Figure 1 under the bias of a spring 62a when the engine is idle, and in the extended position of Figure 2 when fuel pressure has been built up, as to fourteen pounds. A carriage 64 is carried g by the diaphragm 62 and, in turn, carries a pivoted arm 65 having a spring-extended bridging roller 6B to cooperate with a pair of switch contacts G1 and 68. `A stationary stop pin 65?- coacts at times with the arm B5 to cause the roller 66 to bridge the contacts 61 and 68, as will hereinafter be described.

yA solenoid S1 also cooperates with the pivoted arm 65 by reason of its plunger 69 being normally in the extended position of Figure l. Whenever the solenoid S1 is energized the plunger 69 moves to a retracted position.

For controlling the solenoid S1 a stop switch The dia- A tion by a build-up of oil pressure in the oiling system of the engine. For this purpose a bellows chamber 16 is shown diagrammatically, having therein a pressure bellows Tl. Thebellows 'I1 may be collapsed by oil pressure from a conduit '18A against the bias of a spring 19. The conduit I8 leads to the pressure side of the oiling system of the engine. The bellows l1, upon contraction, extends a stem 80 to a position for engaging the toggle lever of the selector switch SSS* when it is in off position and moving it to the on position.

A wire I8 extends from the wire I5 to an auxiliary switch AS. The auxiliary switch is also a toggle switch and itstoggle lever is connected, as by a shaft 11a, with the toggle lever of the selector switch SS3 whereby they may both be manually moved to off position andl will both be automatically moved to "on position by a buildup`of oil pressure. The auxiliaryl switch AS is connected by a wire I9 to the` pump motor PM supplied to the wire I8. When the switch AS is open, an adjustable resistance R1 is in the circuit of the motor, thus slowing it down.

The other side of the switch SS3 is conance R1 is inl series therewith) pumps fuel at a pressure slightly greater than three pounds, and. the by-pass valve 14 maintains the delivered pressure at three pounds. The resistance R1 is made adjustable 'so that it can be set to deliver fuel at a slightly-higher pressure than the pressure at winch the by-pass valve 14 is set.

When theauxiliary switch S is closed, however, the pumpgmotor PM rotates at maximum speed and delivers fuel at'a pressure in excess of eleven pounds for which the by-pass valve i3 is set. Such fuel is delivered through a check valve 8l to the pipe 345 and from there through the conduit 30 to the carburetor C.

A lamp L is connected with the wire l5 to in- /dicate to the pilot the flow of current through the pressure switch PS. A test switch TS is shunted across the pressure switch for the purpose of permitting the pilot to test the circuit, when desired.

A fuel pressure gauge 82 may be connected by a conduit 83 with the `conduit 30 so as to indicate to the pilot the pressure being delivered to the carburetor C. A relatively small conduit 8d is also connected with the conduit 3u and extends to the reserve fuel tank T3.. At its opposite end a oat valve 85 is mounted, the float therefor being indicated at 86, and being operable to close the float valve when the float is rendered buoyant.r The conduit 86 is provided for the purpose of supplying fuel to the reserve tank T3 whenever the level therein recedes below that for which the float 86 is set. Thus I am constantly assured of an adequate reserve supply of fuel in the tank T3 to supply fuel to the electric pump P2 whenever it operates.

Practical operation In the operation of the fuel system described, and of my auxiliary pump therefor, the pilot, when he desires to start the engine, must turn off the selector switch SS3, which also turns off the auxliary'switch AS. He then turns on the 4ignition switch IS. The pressure switch PS is inthe closed position of Figure 1, due to the fuel pressure 'being at zero. Accordingly, current would Abe supplied to the selector valve motor SM if theselector switch SS3 were not open, and thus cause'operation of the selector valve at a time when it is unnecessary.

Closure 'f the ignition switch, besides supplyving current for the ignition system of the engine,

supplies current'through the resistance R1 to the pumpY motor PM. Accordingly, the pump P2 will operate to pump theA fuel to the carburetor, which would otherwise have to be lpumped thereto by a hand pump. The electric pump, therefore, eliminates the operation of a hand pump being imposed upon the pilot. Since the pump motor PM is rotating slowly because of receiving current through the resistor R1, it will build up only slightly more than three pounds pressure, and the excess fuel will be by-passed through the valve lli. The three pounds pressure is insuicient for opening the nozzle 3l of the carburetor as it takes six pounds pressure to open it.

The engine starter may now be operated, which the pressure switchPS opens (see Figure 2).

thereby opening th circuit to the resistor R1 and to the pump motor PM. Since the engine driven pump P1 is now supplying fuel to the carburetor, operation of the pump P11 is no longer necessary. The cut-off of the pressure switch PS will be indicated by the signal lamp L going out.

After the pressure switch PS- has opened there will be a further build-up of oil pressure in the -oil system of the engine, which will soon close the selector switch SS3 andthe auxiliary switch AS. 'I'he circuit to these switches, however, has been broken at the pressure switch so that no circuit is established at this time through switches SS3 and AS. The fuel system will now function in the usual manner, the air eliminator AE eliminating air and vapor whenever such is present inthe housing 39 until fuel raises the float d2 to close the-valve lil. Such air and vapor will be eliminated only when its pressure is in excess of ten pounds, or whatever the pressure setting of the pressure control valve 43 is. The check valve tl will prevent flow of the fuel in the wrong direction, and, likewise, when the pump P2 is operating, the check valve 38 will prevent reverse flow of fuel into the air eliminator and the pump P1.

When the pilot stops the engine by opening the ignition switch IS the current is cut off to all parts of the circuit and the engine will stop, resulting in retraction of the stem all of the selector switch SS3 to the position shown in Figure la, and the fuel pressure in the line 63 will drop, resulting in the pressure switch PS receding to the position shown in Figure 1 and effecting bridging of the contacts 61 and F8 by the roller 66. Subsequently, the engine may again be started as already described.

Assume now that the engine is operating and thetank T1 runs out of fuel. The selector valve operation will occur by reason of the fuel pressure in the conduit t3 receding to below thirteen pounds and thereby causing the carriage 64 to move to the'position of Figure .1, effecting movement of the roller 66 from the position of Figure 2 to the position of Figure 1 by reason of the stop4 pin a being engaged by the pivoted lever 65. A circuit is now established through the pressure switch and the selector switch SS3 (now on, be-

cause the pressure of the oil 'system of the engine has been built up due to engine operation) to the solenoid S1 and to the switches SS1 and SS. Energization of the solenoid S2 causes its plunger 5111 to engage the clutch element 5l with motor SM rotates the shafts 59 and 56 and the will also cause the engine driven pump P1 to oper' pass valve `'l2 is set. At thirteen pounds pressure lobe on the cam Il closes the slow switch SS2 to shunt out the resistance R2 and operate the selector valve motor SM at high speed. Thus the motor operates at high speed While changing from one selector valve position to the next, ex-

cept adjacent the end of the positioning of the valve the slow switch SS2 again is opened by the cam 'il and the final aligning of the port 46a of the valve rotor 48 with the next port, -such as $9, is accomplished slowly to permit the port to stop in exact registry as soon as the motor SM and the clutch solenoid S2 are deenergized.

During this iinal aligning movement of the selector valve, fuel is being picked up from the Soon after starting, the y from the position of Figure 1 to the position o f Figure 3, with the switch 66-61-88, however, still in closed position because the solenoid Sl is in energized position (shown dotted in Figure 2 and by solid lines in Figure 3). The solenoid S1 was energized by closure of the stop switchSS1 through wire 2l, and thus the Figure 3 position of the pressure switch assures completion of the selector valve change-over even though pressure has been built up in the switch PS. Finally, when the selector valve is in exact registry, the stop noid S2 to permit its core 5la to return to its initial position or raised position. Deenergization of the clutch solenoid S2 insures instant stopping of the selector valve Without any possibility of over-run, as might ccur if the selector` valve were directly connected with the motor and thereby subject to motor over-run after the ymotor has been deenergized.

The purpose of the selector switch SS3, responsive to pressure in the oil system of the engine, is to insure that the engine must be started before current is supplied to the circuit of the selector valve motor SM. This is necessary because, the pressure in the fuel system, and, consequently, in the pressure switch PS at'the time of starting the f engine, is too low, or, in fact, is substantially zero, and hence the switch PS will be in the closed position of Figure 1 to start the motor SM.'I This would result in the selector valve SV shifting to the next tank, and if the fuel pressure were still low it would shift on to the succeeding tank, even though the tanks were full of fuel. Such operation of the selector valve is unnecessary and desir-1y able because during the shift from one position to the next, i. e., when the port 46a is out of registry with any of the conduits 48, 49 and 50there will be no fuel supply to the pump P1.,

ation when there would be interruption the fuel supply to the main pump P1. Y

The stand pipe 5I makes it possible touse fuel from the reserve tank T3 after the main tank T1v and al1 auxiliary tanks;such as T2 and others not illustrated, have been exhausted;`yet, if fuel is used from the reserve tank before some of the Yothers are exhausted, there will still be some left for the operation of the pump P2. I insure that there will always be va level of fuel, slightly above the stand pipe 5I by returning some of the pumped` fuel through the conduit 84 to the tank 'I3 and controlling it by the oat valve 85.

With my arrangement the air eliminator can be considerably reduced ln size so that its oat mechanism need be large enough only to actuate the iloat valve, and, of course, the parts should be strong enough to withstand shock and vibration. While the pump P2 operates to supply fuel at a time when the selector valve is changing from one position to the other, it does not interfere with operation of the selector valve,

The pump P2 creates a pressure condition in the fuel system for initiating the starting of the engine, and also when the selector motor SM is energized the pump motor PM is also energized,

' but at its high speed, because the auxiliary switch AS is closed at that time due to normal operating oil pressurewhen the engine is running. Thus whenv the fuel system runs out of fuel from one -tank and the selector valve motor is energized,

the pump motor PM is alsoenergized at its high speed to pump fuel from the reserve tank T3 through conduits 15, 35j and 30 to the carburetor at a pressure of eleven pounds. Due to the restriction of the passageways for the. by-pass rewherein a reserve supply of fuel is carried to feed the carburetor C while the selector valve is passing through a cycle of operation. The pump PM operates only at the times desired, i. e.,` when the pressure of the fuel should be built up at the beginning of engine operation and to supply the carburetor with fuel during a selector valve operand also it does not, due to its particular hookup in the circuit, permit the selector valve to operate when there is a fuel pressuredrop due to the engine being stopped, rather than due to actual failure of fuel while the engine is operated. The resistance R1 and the auxiliary switch AS are so arranged and so operated that the pump P2 does not open the nozzle 3| of the carburetor when the engine is starting, but permits the pump P1 to build up a pressure to accomplish this result. However, the pump P2 operates at its high speed when the selector valve motor is enerf gized, and at that time serves as a means to supply fuel for opening the nozzle 3| and caus ing the carburetor to continue to function, even though the pump P1 is only pumping air. Such air, of course, is eventually eliminated through the eliminator AE, and as soon as it is eliminated the fuel pressure rises and opens the switch PS,

thereby deenergizing the pump P2 and deener-Y glzing the circuit for the selector valve motor SM.

Having described one specific embodiment of my invention together with the operation thereof,

closed to meet the requirements of practice without in any manner departing from the spirit and scope of the present invention except as set forth in the claims appended hereto.

I claim as my invention:

1. An auxiliary fuel pump system comprising a plurality of fuel tanks, a lmain fuel pump for pumping fuel from said tanks to a fuel consuming device, a selector valve located between said tanks and said main fuel pump for selecting the tank from which fuel is taken, a fuel pressure switch communicating with thel outlet'of said main fuel pump for controlling said selector valve, an auxiliary fuel pump having an inlet connected l to one of said fuel tanks and an outlet connected to said fu'el consuming device, said auxiliary fuel pump having a high pressure by-pass and a low pressure by-pass' from said outlet to said inlet. an electric motor for operating lsaid auxiliary fuel pump.. a circuit for said electric motor con trolled by said fuel pressure switch, a'resistance for said motor to eie'ct rotation thereof atslow `pressure to said fuel consuming device, said last switch being manually opened upon starting the operationv of the fuel system, and means responsive to the operation of said fuel consuming device to automatically move said last switch to closed position.

2. An auxiliary fuel pump system comprising a plurality of fuel tanks, a main fuel pump and an auxiliary fuel pump for pumping fuel from said tanks to a fuel consuming device, a selector valve located between said tanks and said mainA fuel pump `for selecting the tank from which fuel is taken by said main fuel pump, a fuel pressure switch communicating with the outlet of said mainfuel pump for controlling said selector valve, an auxiliary fuel pump for pumping fuel from oneof said tanks, an electric motor for operating said auxiliary fuel pump, a circuit for said electric motor controlled by said fuel pressure switch, a resistance for said motor to effect rotation thereof at slow speed to thereby deliver fuel at lowpressure to said fuel consuming device, and a switch for shunting said resistance to effect rotation of said motor at high speed to thereby deliver fue] at high pressure to said'fuel consumingdevice.

3. An auxiliary fuel pump system comprising a plurality of fuel tanks, a main fuel pump for ypumping fuel from said tanks to a carburetor or the like, a selector valve located between said fuel tanks and said main fuel pump, an auxiliary fuel pump for pumping fuel from one of said tanks to said carburetor for selecting the tank from Nwhich fuel is taken by said main fuel pump, a fuel pressure switch communicating with the outlet of said main fuel pump for controlling said selector valve; an electric motor for operating said auxiliary fuel pump, and a circuit for said electric motor controlled by said fuel pressure switch.

4. In'an auxiliary fuel pump system, a plurality of fuel tanks one of which is a reserve tank, conduits leading thereform, a main fuel pump for pumping fuel from said tanks to a carburetor of an engine, an auxiliary fuel pump, a selector valve for selecting the tank` from which fuel is taken by said main fuel pump, said selector valve having intakes connected with said conduits and an outlet connected with said carburetor, a fuel pressure switch communicating with the outlet of said main fuel pump for operating said selector valve, said auxiliary fuel pump having an intake conduit connected with said reserve tank and an outlet conduit connected to said carburetor, said auxiliary pump being connected with said fuel pressure switch to be operated thereby whenever said pressure switch operates said selector valve, a stand pipe in said reserve tank connected with one of said first conduits, one of the intakes of said selector valve being connected therewith, a return fuel pipe fromv said carburetor to said reserve tank, anda iioat valve for controlling the replenishing of said reserve tank with fuel from said return fuel pipe.

5. In an auxiliary fuel pump system, a plurality of fuel tanks` o ne of which is a reserve tank, a. main fuel pump for pumping fuel from said ,tanks to a carburetor or-the like, an auxiliary fuel pump for pumping fuel from one of ,said tanks to said carburetor, a selector valve located between said fuel tanks and said main fuel pump for selecting the tank from which fuel is taken by said mainI fuel pump. a fuel pressure switch communicating with the outlet of said main fuel pump for -operating said selector valve, said auxiliary fuel pump receiving fuel from said reserve tank' and delivering it to said carburetor upon operation of the auxiliary pump, said auxiliary pump being connected with said fuel pressure switch to be operated thereby whenever said fuel pressure switch operates said selector valve, a return fuel pipe from said carburetor to said reserve tank, and

a float valve for controlling the replenishing of said reserve tank with fuel from said return fuel pipe. p i

6. An auxiliary fuel pump system comprising a plurality of fuel tanks, a main fuel pump, conduits from said tanks, a selector valve connected with said conduits and with said main fuel pump for selecting the tank from which fuel is taken, an auxiliary fuel pump connected with one of said tanks, a fuel pressure switch responsive to failure of fuel from the tank with which the selector valve is connected, said vswitch energizing a motor for the selector valve to change its position to select another fuel tank, said auxiliary fuel pump having an electric motor for operating the same, a -circuit for said electric motor, an

auxiliary switch and a resistance in said circuitl shunt-connected with each other and both series connected with said fuel pressure switch, said motor rotating at slow speed when said last switch is in open position and at high speed when said last switch is closed to shunt said resistance out of circuit with said motor.

7. .An auxiliary fuel pump system comprising a plurality of fuel sources, a main fuel pump for pumping fuel from the said sources to a carburetor or the like of an engine, an auxiliary fuel pump for pumping fuel from one of said tanks to said carburetor. a selector valve located between said fuel sources and said main fuel pump for selecting the tank from which fuel is taken by said main fuel pump, a fuel pressure switch communicating with the outlet of said-main fuel pump for controlling said selector valve by closure of the switch when the fuel pressure fails, said auxiliary fuel pump being electric motor driven and-having low and high pressure. excess pressure return valves-a circuit for the motor thereof in series with said fuel pressure switch. a resistance for said circuit to effect rotation of said motor at slow speed for delivery-of fuel at low pressure to said carburetor. and a switchfor shunting said resistance to effect rotation of said motor at high Aspeed to deliver fuel at high pressure to said pump delivering fuel from said last-mentioned one of said sources directly to said fuel-consuming device, an electric motor for operating said auxiliary fuel pump, a circuit for said electric motor controlled by said fuel pressure switch, a

resistentie incircuit with said motor lto effect .Il rotation thereof and of said auxiliary fuel pump at slow speed to thereby deliver fuel at llow pressure to said fuel-consuming device, a switch for shunting said resistance to effect rotation of -said motor and said auxiliary fuel pump at high speed to thereby deliver fuel at high pressure to said fuel-consuming device, and check valves between said pumps and said fuel-consuming device to prevent reverse flow of fuel through one of said pumps while the other one is functioning to deliver fuel to the fuel-consuming device. Y

9. An auxiliary fuel pump system comprising a plurality of fuel tanks, a main fuel pump for l ,lz 1 l I 11. An auxiliary fueipump system comprising a plurality of fuel tank's, a main fuel pump for pumping fuel from said tanks to a carburetor or the like having a carburetor fuel admission valve which opens only when the fuel to the carburetor exceeds a predetermined pressure, an auxiliary fuel, pump for pumping fuel from one ofl said tanksto said carburetor, a selector valve located between said fuel tanks and said main fuel pump for selecting the tank from which fuel is taken by said main fuel pump, a fuelpressure. switch i communicating with the outlet of said main fuel pumping fuel from said tanks through an air eliminator to a carburetor .or the like of an engine having a carburetor fuel admission valve which opens only when the fuel to the carburetor exceeds a predetermined pressure, an auxiliary fuel pump for pumping fuel from one of said tanks to saidcarburetor', a selector valve located between said tanks andsaid main fuel pump for selecting the tank from which fuel is taken by said main fuel pump, a fuel pressure switch.y communicating with the outlet of said main fuel pump4 for controlling said selector valve, said auxiliary fuel purnpv having a high pressure excess pressure return valveand a low pressure excess pressure return valve, said low pressure excess pressure return valve being set to operate at avlower pressure than the carburetor valve, an Aelectric motor for operating said auxiliary fuel pump. a circuit for said electric motor controlled by said fuel pressure switch, a resistance for said circuit to effect rotation of said motor atslow speed for delivery of fuel to said carburetor at a pressure low enough to prevent discharge of -the fuel into the engine through the carburetor valve, a switch for shunting said resistance to enect rotation of said motor at high speed to deliver fuel at operating pressure to said carburetor, and

the carburetor and between said air eliminator and the carburetor to prevent reverseflow of fuel into the auxiliary pump when the main pump is properly delivering fuel and for preventing reverse flow of fuel into the air eliminator when the auxiliary pump is delivering fuel to the carburetor. Y

10. vAn auxiliary fuel pump system for an engine comprising a plurality of fuel tanks. a main fuel pump for pumping fuel from said tanks through an air eliminator to a carburetor or the like having -a carburetor fuel admission valve that opens only when the fuel to the carburetor exceeds a predetermined pressure, an auxiliary fuel pumpfor pumpingl fuel from one of said tanks to said carburetor, a selector valve located between 'said fuel tank and said main fuel pump for selecting the tank from which fuel is taken by said main fuel pump, a fuel pressure switch communicating with the outlet of said main fuel pump for controlling said selector valve. an electric motor for operating said auxiliary fuel pump,'

` motorv at high speedzto deliver fuel at operating pressure to said carburetor, and check valves between said auxiliary pump and the carburetor and between said air eliminator and the carburetor andopening toward the cai'btlltr.

pump for selecting the tank fromwhich fuel is taken by said fuel pump, a fuel pressure switch communicating with @e outlet of said main fuel pump for controlling said selector'valve, an electric motor for operating said auxiliary fuel pump, a circuit for said electric motor controlled by said fuel pressure switch, a resistance for said circuit to effect rotation of said motor at slow speed fordelivery of fuel to said carburetor at a pressure low enough for the carburetor valve to prevent discharge of -the fuel into the engine, and a switch for shunting said resistance to effect rotation of said motor at high speed to deliver fuel at operating pressure to said carburetor.

12. An auxiliary fuel pump system comprising a plurality of .fuel tanks, a main fuel pump for pumping fuel from said tanks to a carburetor or the like of an engine having a, carburetor fuel admission valve that opens only when fuel to the carburetorexceeds a predetermined pressure, an auxiliary fuel pump for pumping fuel from one of said'tanks to said carburetor, a selector valve, located between said fuel tanks and said main fuel pump for selecting the tank from whi ch fuel is taken by said main fuel pump, and a fuel pressure switch operative to close when the fuel pressure through said selector valve'and from said main fuel pump fails due to failure of fuel from the tank with which the selector valve is connected, said switch energizing va motor for the selector valve to change its position to another.

fuel tank, said auxiliary fuel pump having van electric motor for operating the same. a circuit for said electric motor. an auxiliary switch and a resistance in said circuit shunt-connected with of fuel from said carburetor to the engine at av pressure low enoughv for the carburetor valve to prevent discharge of the fuel thereinto when said auxiliary switch is'in open position and to'effect rotation of said motor at high speed to deliver fuel and operating pressure to said carburetor when said auxiliary switch is closed;

HOWARD A. S

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number v Name Date 2.275.471 Samiran ;L'Mar. 10, 1942 2.275 472 `Samiran Mar; 10, 1942 1,329.99? 'Page Feb. 3, .1920 1,404,152 Kettering Jan. 1'7, 1922 2.183.586. lPhillips et al. s---" Dec. 19,' 1939 2,924.133 Harding-; Dec. 10, 1935- 1,835.615 Robert Dec. 8, 1931 2.149.545 .Price Marl, 1939 2.327.373 Samiran Aug. 24, 1943 2,314,900 Samiran Mar, 30, 1943 

